1. Technical Field
The present disclosure relates to a light emitting diode (LED) and a method for making the same.
2. Description of Related Art
LEDs are semiconductors that convert electrical energy into light. Compared to conventional light sources, LEDs have higher energy conversion efficiency, higher radiance (i.e., they emit a larger quantity of light per unit area), longer lifetime, higher response speed, and better reliability. At the same time, LEDs generate less heat. Therefore, LED modules are widely used as light sources in optical imaging systems, such as displays, projectors, and so on.
A conventional method of making the LEDs includes the following steps. A buffer layer, a first semiconductor layer, an active layer, and a second semiconductor layer are deposited on a substrate by a metal organic chemical vapor deposition (MOCVD) method. The second semiconductor layer and the active layer are etched via an inductance-coupling plasma etch process, thereby exposing a surface of the first semiconductor layer. A first electrode is deposited on a top surface of the first semiconductor layer via an electron beam evaporation process. A second electrode is formed on the second semiconductor layer via the electron beam evaporation process. To improve the light extraction efficiency of the LEDs, the second semiconductor is etched via the inductance-coupling plasma etch process to roughen a top surface. The roughened top surface is defined as the light extraction surface. However, in the above method, etching the light extraction surface to roughen the top surface thereof is a complex manufacturing process and has a high manufacturing cost. Furthermore, during the etching process, the lattice structure of the semiconductor layer may be destroyed.
What is needed, therefore, is a light emitting diode that can overcome the above-described shortcomings.